%0 Journal Article
%T The Underlying Mechanisms: How Hypothyroidism Affects the Formation of Common Bile Duct Stones¡ªA Review
%A Johanna Laukkarinen
%A Juhani Sand
%A Isto Nordback
%J HPB Surgery
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/102825
%X For decades, one well-known risk factor for the development of gallbladder stones has been hypothyroidism. Recent studies have interestingly reported that the risk in particular for common bile duct (CBD) stones increases in clinical and subclinical hypothyroidism. There are multiple factors that may contribute to the formation and/or accumulation of CBD stones in hypothyroid patients, including decreased liver cholesterol metabolism, diminished bile secretion, and reduced sphincter of Oddi relaxation. This paper focuses on the mechanisms possibly underlying the association between hypothyroidism and CBD stones. The authors conclude that when treating patients with CBD stones or microlithiasis, clinicians should be aware of the possible hypothyroid background. 1. Introduction Several factors affecting bile content and bile flow are involved in the complex pathogenesis of gallstones. In hypothyroidism, not only the risk for gallbladder stones [1, 2], but also the risk for common bile duct (CBD) stones in particular is increased [3¨C5]. Impaired liver cholesterol metabolism [6], diminished bile secretion [7], and reduced sphincter of Oddi (SO) relaxation [8, 9] may contribute to the formation and/or accumulation of CBD stones in hypothyroid patients. In this paper the possible mechanisms underlying the association between hypothyroidism and CBD stones are being discussed. 2. Review Criteria PubMed was searched in April 2011 with the terms ¡°hypothyroidism,¡± ¡°subclinical hypothyroidism,¡± ¡°thyroxine,¡± ¡°thyroid function,¡± ¡°gallstones,¡± ¡°bile duct stones,¡± ¡°sphincter of Oddi,¡± ¡°biliary motility,¡± ¡°cholesterol metabolism,¡± and ¡°hepatic secretion¡± for full-length English language original publications and review articles published between 1950 and 2010 (initial inclusion criteria). Abstracts and articles not relevant to the topic were excluded. A total of 3472 publications were identified at the initial step, out of which 3396 were excluded and 76 were finally considered. The search was updated in August 2012. 3. Prevalence of Clinical and Subclinical Hypothyroidism in CBD Stone Patients Several recent studies report an association between hypothyroidism, or subclinical hypothyroidism, and CBD stones (Table 1). In a retrospective study on patients over 60 years of age [3], it was noted for the first time that CBD stone patients have significantly more diagnosed hypothyroidism (11%), not only when compared to control patients from whom gallstones had been excluded (2%), but also when compared to gallbladder stone patients without CBD stones (6%). In this study,
%U http://www.hindawi.com/journals/hpb/2012/102825/